1. Field of the Invention
The present invention relates to a pressure sensor having a pressure sensor IC mounted on a board, in particular, applicable to an intake system pressure detection device for an internal combustion engine.
2. Description of Related Art
Conventionally, intake pressure of an intake system module for an internal combustion engine has been detected by a pressure sensor as an intake system pressure detection device. A conventional structure for detecting intake pressure is shown in FIG. 5. An intake system module 1 is composed of an air inlet 2, an air cleaner 3, an intake duct 4, a throttle body 5, a surge tank 6, an intake manifold 7 and so on, which are combined with one another and joined together into an integrated body. An intake air passage is formed in the intake system module 1.
The intake system module 1 is mounted on an engine 8. Intake air is supplied to engine 8 through the air inlet 2, the air cleaner 3, the intake duct 4, the throttle body 5, the surge tank 6 and the intake manifold 7.
ECU 9 incorporating various parts and components for engine control (engine control devices) including a sensor IC 13 for detecting intake pressure in the surge tank 6 is installed in an adequate place. An end of a rubber hose 10 is connected to ECU 9 for introducing pressure and the other end of the rubber hose 10 is connected to a connection port 6a formed to communicate with an interior of the surge tank 6. As shown in FIG. 6, the sensor IC 13 is mounted on a board 12 accommodated in a case 11 of ECU 9. The sensor IC 13 has a pressure sensor element (not shown) covered with resin 13a by molding and a pressure introduction pipe 13b protruding outward from an outer surface of the resin 13a. 
The case 11 is provided with a hose insertion bore 11a where an axial end of the pressure introduction pipe 13b is positioned. The end of the rubber hose 10 is inserted into the hose insertion bore 11a and connected to the pressure introduction pipe 13b. 
However, the conventional structure, in which the rubber hose 10 connects ECU 9 with the surge tank 6 whose interior pressure is detected, has a drawback in that productivity of manufacturing ECU 9 is lower and ECU 9 is manufactured at higher cost. In case of the sensor IC 13 having the pressure introduction pipe 13b protruding outward from an outer surface thereof, it becomes necessary to mount the sensor IC 13 on the board 12 manually or with a special purpose mounting equipment, since a commonly used vacuum type mounting equipment, with which it is very difficult to attract or adhere the sensor IC, can not be used.
Further, the rubber hose 10 is likely worn out or broken due to vibration that may cause a contact between the rubber hose 10 and the case 11 or the vibration transmitted to the sensor IC 13 is likely to cause contact failure between a terminal 13c and a solder 12a. Furthermore, the pressure sensor having the conventional structure is not simple and compact as an intake system pressure detection device, since it requires the rubber hose 10 whose installation takes time and is troublesome.